Devices, softwares and methods for handling off live calls between legs of CSV and VoX modalities

ABSTRACT

Devices, softwares methods hand off a live call from an original leg of a first modality (such as Circuit Switched Voice) to an alternate leg of another modality (such as Voice over Internet Protocol). An original leg of a call is established using the first modality. Then the alternate leg of the call is established using the second modality, while the first leg is still established. Then the call is handed off from the original leg to the alternate leg, while the connection is active.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.10/086,673, filed on Feb. 28, 2002 now U.S. Pat. No. 7,003,298, which isnow pending, and is herein incorporated by reference in it's entiretyfor all intents and purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to the field of handling voicetelephone call connections, and more specifically to devices, softwaresand methods for handing off voice telephone calls made between circuitswitched telephone connections and data network packet switchedconnections.

2. Description of the Related Art

Traditionally telephone calls are handled through connections that usecircuit switching. These connections are also known as circuit switchedvoice connections.

Current networks for cellular communication devices (such as cellulartelephones) are characterized as 2G/2.5G, which means “secondgeneration”, and “second and a half generation”. These, along with thefirst versions of 3G (“third generation”) cellular networks, use circuitswitched connections for voice calls.

Packet switched networks, such as the internet, were initially intendedto be for transmitting data, which is why they are also sometimes calleddata networks. Packet switched networks can also handle telephone calls.Connections for voice telephone calls through a network are also calledpacket switched connections.

In a packet switched connection across a data network, the voice data ofa conversation is transmitted in data packets, using a suitable voiceover data network (VoX) protocol. A VoX protocol, also known as merelyVoX, is an application that operates on top of the data network. SuchVoX protocols include but are not limited to the Voice over InternetProtocol (VoIP), the Voice over Frame Relay (VOFR) protocol, Voice overAsynchronous Transfer Mode (VoATM) protocol, etc.

Wireless LANs (Local Area Networks) are packet switched, and can providevoice service using VoX. These wireless LANs (“WLANs”) include thoseoperating under the IEEE 802.11b/a standard. “IEEE” stands for theInstitute of Electrical and Electronics Engineers, an organizationmaintaining a website at <http://www.ieee.org/> at the time that thisdocument is initially filed with the U.S.A. Patent Office.

For data transmission services, multimodal WLANs and cellular handsetsmight use either WLANs or cellular connections. In fact, it is evenpossible to perform a data handoff between legs of communication thatare of disparate such modalities.

It is desired to have a way to hand off telephone call connectionsbetween the CSV modality and the VoX modality.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes these problems and limitations of theprior art.

Generally, the present invention provides devices, softwares and methodsfor handing off a live call from an original leg of a first modality(such as CSV) to an alternate leg of another modality (such as VoX). Thedevices may be wireless telephones, voice gateways, etc.

An original leg of a call is established using the first modality. Thenthe alternate leg of the call is established using the second modality,while the first leg is still established. Then the call is handed offfrom the original leg to the alternate leg, while the connection isactive.

The invention offers the advantage that the handoff between the CSVmodality and the VoX modality is automatic, without discontinuing thecall. This enables providing voice service over a hybrid packetswitched/circuit switched network, such as a WLAN/cellular network.Optionally it could take place automatically, without user activation.

The invention will become more readily apparent from the followingDetailed Description, which proceeds with reference to the drawings, inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless station made according to anembodiment of the invention.

FIGS. 2A-2D are diagrams illustrating successive stages as the device ofFIG. 1 implements a method according to the invention.

FIG. 3 is a block diagram of a network device made according to anembodiment of the invention.

FIGS. 4A-4E are diagrams illustrating successive stages as the device ofFIG. 3 implements a method according to the invention.

FIG. 5 is a flowchart illustrating a method according to an embodimentof the present invention.

FIG. 6 is a flowchart illustrating a method according to yet anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

As has been mentioned, the present invention provides devices, softwaresand methods for handing off a live call from an original leg of a firstmodality to an alternate leg of another modality. The invention is nowdescribed in more detail.

Referring now to FIG. 1, a wireless station 100 made according to anembodiment of the invention is described in more detail. Wirelessstation 100 is a dual mode wireless device, such as a cellulartelephone.

Station 100 includes a speaker 110, and a microphone 120, for use by aperson.

Station 100 also includes a physical component 130 for wirelesscommunication with other devices. Component 130 may include one or moretransmitting and receiving antennas that use radio frequency (RF) waves.Component 130 may include two subcomponents (not shown separately), onefor CSV and one for data network communication.

Station 100 also has a processor 140. Processor 140 may be implementedas a Digital Signal Processor (DSP), Central Processing Unit (CPU), orany other equivalent way known in the art.

Processor 140 includes a memory 142, on which a program 144 may reside.Functions of processor 140 may be controlled by program 144, as willbecome apparent from the below.

Station 100 is dual mode. This is implemented by processor 140 having acircuit switched voice (CSV) modality communication component 146, and anetwork voice (VoX) modality communication component 148.

In addition, processor 140 has a handoff functionality HOM 149, as willbe described below. This operates to handoff calls between the twomodes, as is described below. In some embodiments, handoff functionalityHOM 149 may be implemented through program 144.

Processor 140 is coupled with speaker 110 and microphone 120 via a voicechannel 150. In the case of device 100, voice channel 150 is internal,although that is not necessary for practicing the invention. A number ofdata paths may be considered as voice channels.

Processor 140 is also coupled with component 130. In particular, CSVcomponent 146 is coupled with physical communication component 130 viaCSV channel 160, and VoX component 148 is coupled with physicalcommunication component 130 via VoX channel 170. If component 130 ismade of two subcomponents, they are coupled accordingly. In otherembodiments, physical communication component 130 may be part ofprocessor 140.

Referring now to FIGS. 2A-2D, successive stages are illustrated asstation 100 uses its handoff functionality HOM 149 to hand off a callaccording to the invention. In the example of FIGS. 2A-2D, a VoX call isestablished first, and is handed off to a circuit switched call.

In FIGS. 2A-2D, station 100 communicates with a device 220, which isalso dual mode. In this example, device 220 has a CSV port 224 and a VoXport 226. In other embodiments, device 220 can have the same physicalport for both communication modes. In yet other embodiments, device 220can be two separate devices, of possibly different networks. One ofthese devices would include CSV port 224, and the other would includeVoX port 226.

Device 220 ultimately communicates with a telephone (not shown), via avoice channel. That telephone includes a microphone and a speaker foruse by another user. Communication can be direct, or involve other legs.

As seen in FIG. 2A, station 100 establishes a connection 260 with VoXport 226 of device 220. Connection 260 is further coupled with VoXchannel 170. Packets 265 are exchanged over connection 260, and alsoover VoX channel 170 within station 100.

Next, as seen in FIG. 2B, station 100 also establishes a connection 240with CSV port 224 of device 220. This is while connection 260 is stillestablished, and further optionally while packets 265 are still beingexchanged.

Next, as seen in FIG. 2C, signals 245 are exchanged over connection 240,and also over channel 160 within station 100. This may be whileconnection 260 is still established.

Next, as seen in FIG. 2D, connection 260 is torn down.

It will be appreciated that the illustrated sequence is amake-before-break sequence. In other words, connection 240 is madebefore connection 260 is torn down.

The shown sequence of stages is only one of many possible suchsequences. For example, the sequence can be inverted, to start with aCSV and switch to VoX. The person skilled in the art will discern thetechnical implementation details.

One of the implementation features has to do with a decision of whethersome of the initial signals for the handoff will be sent in-band (andmay therefore be audible to the users), or out of band (better qualityof service). These include the modality handoff signal, address signals,etc., as described later in this document.

Sending the initial signals out of band may require additionalprovisions. One group of embodiments may require the prior existence ofa well-known server, such as a registration server. A handoff VoIPgateway would preregister with the well known server using aCSV-identifier (ANI/DN), and a corresponding VoX access address (whichis preferably a port address). The CSV-identifier may be a dial Number(DN), or an Automatic Number Identification (ANI).

First, then, the original leg of a telephone call is established with aremote device using the CSV modality. Then the remote device registerswith the registration server, with its CSV-identifier and correspondingVoX access address.

Then the hand-off takes place as follows. If the device does not knowthe VoX access address of the remote device, it queries the registrationserver using the CSV-ID (ANI/DN), to get the VoX access address.

Then a VoX handoff call, which contains at least an implicit or explicithandoff signal, is made to the remote device using the access address.The handoff signal includes the identifier (ANI/DN) of the CSV call-leg.Once the second leg has also established, handing off proceeds asdescribed above.

Referring now to FIG. 3, a network switch 300 made according to anembodiment of the invention is described in more detail. Switch 300 maybe any network switch, such as a voice gateway, a gateway, a router, abridge, etc.

Switch 300 is made to operate concurrently in a CSV network 314 and aVoX network 316. CSV network 314 may be a relevant cellular network,optionally with the Public Switched Telephone Network (PSTN). VoXnetwork 316 is a packet switched network on which a VoX application isrunning. In some instances of the invention, network 314 and network 316may be combined into a single network, which may be a hybrid network.

Switch 300 has a network interface 320 for interfacing with networks314, 316. Network interface 320 may be implemented by two components,namely a CSV component and a VoX component, as will be clear to a personskilled in the art.

Network interface 320 may have a CSV port 324 and a VoX port 326. CSVport 324 interfaces with CSV network 314, and VoX port 326 interfaceswith VoX network 316.

Network interface 320 may also have a general port 328, which is eithera CSV port or a VoX port. In either case, general port 328 interfaceswith the appropriate one of networks 314, 316. In the case of FIG. 3,port 328 is a VoX port, interfacing with VoX network 316, but that isonly as an example, and not as a limitation.

Switch 300 also has a processor 340 coupled with network interface 320.Processor 340 may be implemented as a Digital Signal Processor (DSP),Central Processing Unit (CPU), or any other equivalent way known in theart.

Switch 300 additionally includes a memory 360, on which a program 370may reside. Functions of processor 340 may be controlled by program 370,as will become apparent from the below.

Processor 340 also includes a handoff functionality HOR 380. Thisoperates to handoff calls, as is described below. In some embodiments,handoff functionality HOR 380 may be implemented through program 370.

Referring now to FIGS. 4A-4E, successive stages are illustrated asnetwork switch 300 uses its handoff functionality HOR 380 to hand off acall according to the invention. The shown sequence of stages is onlyone of many possible such sequences. For example, the sequence can beinverted as per the above.

In FIGS. 4A-4E, network switch 300 communicates with a device 420, whichis also a dual mode device. The handoff takes place between CSV port 324and VoX port 326.

In addition, network switch 300 ultimately communicates with a telephone430, which includes a microphone and a speaker. The communication isthrough a voice channel that starts from port 328.

In other words, network switch 300 facilitates the communication betweendevice 420 and telephone 430. It does that by internally coupling port328 with the appropriate one of ports 324, 326.

As seen in FIG. 4A, network switch 300 establishes a VoX connection 460with VoX port 326 through VoX network 316. Port 326 is additionallycoupled with port 328.

Next, as seen in FIG. 4B, network switch 300 establishes an additionalCSV connection 440 with CSV port 324 through CSV network 314. This ispreferably while connection 460 is still established.

Referring next to FIG. 4C, an optional step is seen. Both CSV connection440 and VoX connection 460 are established. Data goes from telephone430, through port 328 to device 420 through either CSV connection 440 orVoX connection 460.

In addition, data is received from both CSV connection 440 and VoXconnection 460. The received data is then added in an adder 470 ofprocessor 340. The added data is played to telephone 430 through port328.

Next, as seen in FIG. 4D, network switch 300 uses VoX connection 440exclusively. Port 324 is additionally coupled with port 328. That maybewhile connection 460 is still established.

Next, as seen in FIG. 4E, VoX connection 460 is torn down.

It will be appreciated that the illustrated sequence is amake-before-break sequence. In other words, connection 440 is madebefore connection 460 is torn down.

The present invention may be implemented by one or more devices thatinclude logic circuitry. The device performs functions and/or methods asare described in this document. The logic circuitry may include aprocessor that may be programmable for a general purpose, or dedicated,such as microcontroller, a microprocessor, a Digital Signal Processor(DSP), etc. For example, the device may be a digital computer likedevice, such as a general-purpose computer selectively activated orreconfigured by a computer program stored in the computer.

Moreover, the invention additionally provides methods, which aredescribed below. The methods and algorithms presented herein are notnecessarily inherently associated with any particular computer or otherapparatus. Rather, various general-purpose machines may be used withprograms in accordance with the teachings herein, or it may prove moreconvenient to construct more specialized apparatus to perform therequired method steps. The required structure for a variety of thesemachines will become apparent from this description.

In all cases there should be borne in mind the distinction between themethod of the invention itself and the method of operating a computingmachine. The present invention relates both to methods in general, andalso to steps for operating a computer and for processing electrical orother physical signals to generate other desired physical signals.

The invention additionally provides programs, and methods of operationof the programs. A program is generally defined as a group of stepsleading to a desired result, due to their nature and their sequence. Aprogram made according to an embodiment of the invention is mostadvantageously implemented as a program for a computing machine, such asa general-purpose computer, a special purpose computer, amicroprocessor, etc.

The invention also provides storage media that, individually or incombination with others, have stored thereon instructions of a programmade according to the invention. A storage medium according to theinvention is a computer-readable medium, such as a memory, and is readby the computing machine mentioned above.

The steps or instructions of a program made according to an embodimentof the invention requires physical manipulations of physical quantities.Usually, though not necessarily, these quantities may be transferred,combined, compared, and otherwise manipulated or processed according tothe instructions, and they may also be stored in a computer-readablemedium. These quantities include, for example electrical, magnetic, andelectromagnetic signals, and also states of matter that can be queriedby such signals. It is convenient at times, principally for reasons ofcommon usage, to refer to these quantities as bits, data bits, samples,values, symbols, characters, images, terms, numbers, or the like. Itshould be borne in mind, however, that all of these and similar termsare associated with the appropriate physical quantities, and that theseterms are merely convenient labels applied to these physical quantities,individually or in groups.

This detailed description is presented largely in terms of flowcharts,display images, algorithms, and symbolic representations of operationsof data bits within at least one computer readable medium, such as amemory. An economy is achieved in the present document in that a singleset of flowcharts is used to describe both methods of the invention, andprograms according to the invention. Indeed, such descriptions andrepresentations are the type of convenient labels used by those skilledin programming and/or the data processing arts to effectively convey thesubstance of their work to others skilled in the art. A person skilledin the art of programming may use these descriptions to readily generatespecific instructions for implementing a program according to thepresent invention.

Often, for the sake of convenience only, it is preferred to implementand describe a program as various interconnected distinct softwaremodules or features, individually and collectively also known assoftware and softwares. This is not necessary, however, and there may becases where modules are equivalently aggregated into a single programwith unclear boundaries. In any event, the software modules or featuresof the present invention may be implemented by themselves, or incombination with others. Even though it is said that the program may bestored in a computer-readable medium, it should be clear to a personskilled in the art that it need not be a single memory, or even a singlemachine. Various portions, modules or features of it may reside inseparate memories, or even separate machines. The separate machines maybe connected directly, or through a network, such as a local accessnetwork (LAN), or a global network, such as the Internet.

It will be appreciated that some of these methods may include softwaresteps which may be performed by different modules of an overall parts ofa software architecture. For example, data forwarding in a router may beperformed in a data plane, which consults a local routing table.Collection of performance data may also be performed in a data plane.The performance data may be processed in a control plane, whichaccordingly may update the local routing table, in addition toneighboring ones. A person skilled in the art will discern which step isbest performed in which plane.

In the present case, methods of the invention are implemented by machineoperations. In other words, embodiments of programs of the invention aremade such that they perform methods of the invention that are describedin this document. These may be optionally performed in conjunction withone or more human operators performing some, but not all of them. As perthe above, the users need not be collocated with each other, but eachonly with a machine that houses a portion of the program. Alternately,some of these machines may operate automatically, without users and/orindependently from each other.

It will be appreciated that some of these methods may include softwaresteps which may be performed by different modules of an overall parts ofa software architecture. For example, data forwarding in a router may beperformed in a data plane, which consults a local routing table.Collection of performance data may also be performed in a data plane.The performance data may be processed, and accordingly used in a controlplane to update the local routing table, in addition to neighboringones. A person skilled in the art will discern which step is bestperformed in which plane.

Methods of the invention are now described.

Referring now to FIG. 5, a flowchart 500 is used to illustrate a methodaccording to another embodiment of the invention. The method offlowchart 500 may also be practiced by device 100 of FIG. 1, and device300 of FIG. 3.

According to a box 510, an original leg of a telephone call connectionis established. The connection uses the VoX modality or the CSVmodality.

The connection is with a remote device, such a device 220. This applieswhether device 220 is a single unit, or a group of units, in one or morenetworks.

According to an optional next box 520, the original leg is coupled witha voice channel for transferring data between them. The voice channelmay be internal within a device or external, and terminates in at leastone of a speaker and a microphone. When the voice channel is external,it may use an outgoing call leg over a circuit switched or packetswitched network.

According to a next box 525, data of a voice conversation is transferredbetween the original leg and the voice channel. The data is transferredpursuant to the telephone call connection.

According to an optional next box 530, a modality handoff signal isexchanged with the remote device. This is to signify that the handoffprocess is to start, and may be performed automatically, without theuser initiating it.

Exchanging the modality handoff signal may be performed by transmittingit to the remote device over the original leg. Alternately, exchangingthe modality handoff signal is performed by receiving it from the remotedevice over the original leg.

According to a next box 540, an address signal is received from theremote device. The address signal encodes an access address. Preferablythe address signal is received responsive to exchanging the modalityhandoff signal. Alternately, the address signal is received responsiveto querying.

Depending on the modality, the access address may be a Dial Number (DN)for a CSV connection, or a port address for a VoX connection, or anAutomatic Number Identification (ANI). The ANI may be a series of digitsincluded in the call, identifying the telephone number of the callingdevice. In other words, ANI identifies the number of the calling party.

According to a next box 543, a handoff call is made to the accessaddress. The handoff call is made responsive to receiving the addresssignal, automatically and with no user interaction.

According to a next box 546, an alternate leg of the telephone callconnection with the remote device is established from the handoff call.This is made while the original leg is still established. The alternateleg uses the opposite modality from that of the original leg establishedat box 510.

According to an optional next box 550, the alternate leg is coupled withthe voice channel.

According to a next box 560, data of the voice conversation istransferred between the voice channel and the alternate leg. The data istransferred pursuant to the telephone call connection.

According to a next box 570, the original leg is torn down. That takesplace while transferring data of the voice conversation between thevoice channel and the alternate leg.

According to an optional box 575, prior to box 560, data is receivedfrom both the original leg and the alternate leg. According to a nextbox 580, the received data is combined to form a combined data stream ofa single modality (either CSV or VoX). Prior to combining, one of thedata streams is converted to be of the other modality.

Box 580 thus accomplishes a soft handoff, for a certain handoff period.If done by a voice gateway, it may use VoX frames when there is nopacket loss, and CSV frames where there is packet loss.

According to an optional box 590, a delay is adjusted in either theoriginal leg or alternate leg, to synchronize the voice data streams.This is performed prior to combining in box 580.

According to another box 593, a difference in delay is determinedbetween transferring data along the original leg and along the alternateleg. This is performed for the adjustment of box 590.

Alternately, according to another box 596, the exchange of data isanalyzed to detect a silent period, prior to the transfer of box 560.

Referring now to FIG. 6, a flowchart 600 is used to illustrate a methodaccording to yet another embodiment of the invention. The method offlowchart 600 may also be practiced by device 100 of FIG. 1, and device300 of FIG. 3.

According to a box 610, an original leg of a telephone call connectionis established. The connection is with a remote device, and uses the VoXmodality. Alternately, the connection may use the CSV modality.

According to an optional next box 620, the original leg is coupled witha voice channel for transferring data between them. The voice channelmay be internal within a device or external, and terminates in at leastone of a speaker and a microphone.

According to a next box 625, data of a voice conversation is transferredbetween the original leg and the voice channel. The data is transferredpursuant to the telephone call connection.

According to an optional next box 630, a modality handoff signal isexchanged with the remote device. This is to signify that the handoffprocess is to start, and may be performed automatically, without theuser initiating it.

Exchanging the modality handoff signal may be performed by transmittingit to the remote device over the original leg. Alternately, exchangingthe modality handoff signal is performed by receiving it from the remotedevice over the original leg.

According to a next box 635, an identity code is received from theremote device about the original leg.

According to an optional next box 640, an address signal is transmittedto the remote device. The address signal encodes an access address.Preferably the address signal is received responsive to exchanging themodality handoff signal. Depending on the modality, the access addressmay be a dial number for a CSV connection, or a port address for a VoXconnection.

According to a next box 643, a handoff call is received at the accessaddress. The handoff call is expected to be received, responsive totransmitting the address signal.

According to a next box 646, an alternate leg of the telephone callconnection with the remote device is established from the handoff call.This is made while the original leg is still established. The alternateleg uses the opposite modality from that of the original leg establishedat box 610.

According to an optional next box 650, the alternate leg is coupled withthe voice channel. The identity code is used to identify the appropriateport, for appropriate matching.

According to a next box 660, data of the voice conversation istransferred between the voice channel and the alternate leg. The data istransferred pursuant to the telephone call connection.

According to a next box 670, the original leg is torn down. That takesplace while transferring data of the voice conversation between thevoice channel and the alternate leg.

According to an optional box 675, prior to box 660, data is receivedfrom both the original leg and the alternate leg. According to a nextbox 680, the received data is combined to form a combined data stream ofa single modality (either CSV or VoX). Prior to combining, one of thedata streams is converted to be of the other modality. This is analogousto the soft handoff of boxes 575 and 580.

According to an optional box 690, a delay is adjusted in either theoriginal leg or alternate leg, to synchronize the voice data streams.This is performed prior to combining in box 680.

According to another box 693, a difference in delay is determinedbetween transferring data along the original leg and along the alternateleg. This is performed for the adjustment of box 690.

Alternately, according to another box 696, the exchange of data isanalyzed to detect a silent period, prior to the transfer of box 660.

A person skilled in the art will be able to practice the presentinvention in view of the description present in this document, which isto be taken as a whole. Numerous details have been set forth in order toprovide a more thorough understanding of the invention. In otherinstances, well-known features have not been described in detail inorder not to obscure unnecessarily the invention.

While the invention has been disclosed in its preferred form, thespecific embodiments as disclosed and illustrated herein are not to beconsidered in a limiting sense. Indeed, it should be readily apparent tothose skilled in the art in view of the present description that theinvention may be modified in numerous ways. The inventor regards thesubject matter of the invention to include all combinations andsubcombinations of the various elements, features, functions and/orproperties disclosed herein.

The following claims define certain combinations and subcombinations,which are regarded as novel and non-obvious. Additional claims for othercombinations and subcombinations of features, functions, elements and/orproperties may be presented in this or a related document.

1. A device comprising: a physical component for wireless communication;and a processor coupled with the physical component, in which theprocessor is adapted to establish an original leg of a telephone callconnection with a networking endpoint over one of a circuit-switchednetwork or a packet-switched network, where the networking endpoint isdirectly coupled to both the circuit-switched network and thepacket-switched network; transfer data of a voice conversation betweenthe original leg and a voice channel that terminates in one of a speakerand a microphone pursuant to the telephone call connection; exchange ahandoff signal with the networking endpoint over the original leg of thetelephone call connection after transferring data of the voiceconversation over the original leg to the networking endpoint; establishan alternate leg of the telephone call connection with the networkingendpoint over the other one of the circuit-switched network or thepacket-switched network while the original leg is still establishedresponsive to the handoff signal and transfer data of the voiceconversation between the voice channel and the alternate leg pursuant tothe telephone call connection.
 2. The device of claim 1 where theprocessor is configured to tear down the original leg while transferringdata of the voice conversation between the voice channel and thealternate leg.
 3. The device of claim 1 where the processor isconfigured to exchange the handoff signal after transferring voice dataover the original leg.
 4. The device of claim 1 where the processor isconfigured to access a registration server to identify an access addressand to transmit the handoff signal to the access address.
 5. The deviceof claim 1 where the processor is configure to receive voice data fromboth the original leg and the alternate leg; and combine the voice datareceived from the original leg and from the alternate leg to form acombined voice data stream.
 6. A method comprising: establishing a firstvoice connection with a networking device over one of a circuit-switchednetwork or a packet-switched network; exchanging voice data and at leastone handoff signal with the networking device over the first voiceconnection, where the at least one handoff signal is exchanged with thenetworking device after exchanging the voice data over the first voiceconnection to the networking device; establishing a second voiceconnection with the networking device over the other one of thecircuit-switched network or the packet-switched network responsive tothe handoff signal while the first voice connection is stillestablished; and sending the voice data associated with the first voiceconnection with the networking device over the second voice connectionwith the networking device.
 7. The method of claim 6 includes receivingthe handoff signal from the networking device over the first voiceconnection; and initiating the establishment of the second voiceconnection with the networking device responsive to the handoff signal.8. The method of claim 6 includes sending the handoff signal to thenetworking device over the first voice connection; and receiving aninitiation of the second voice connection from the networking device. 9.The method of claim 8 includes accessing a registration server todetermine an access address associated with the networking device; andsending the handoff signal to the access address.
 10. The method ofclaim 6 includes tearing down the first voice connection with thenetworking device after sending the voice data over the second voiceconnection with the networking device.
 11. The method of claim 10includes exchanging voice data and at least one handoff signal with thenetworking device over the second voice connection; establishing a thirdvoice connection with the networking device over the same network as thefirst voice connection responsive to the handoff signal; and sending thevoice data associated with the second voice connection with thenetworking device over the third voice connection with the networkingdevice.
 12. The method of claim 6 includes combining voice data receivedfrom both the first voice connection and the second voice connectioninto a voice data stream for auditory presentation at a phone endpoint.13. A computer-readable medium containing computer instructions that,when executed, cause a processor or multiple communicating processors toperform a method comprising: establishing a first voice connection witha networking device over one of a circuit-switched network or apacket-switched network; exchanging voice data and at least one handoffsignal with the networking device over the first voice connection, wherethe at least one handoff signal is exchanged with the networking deviceafter exchanging the voice data over the first voice connection to thenetworking device; establishing a second voice connection with thenetworking device over the other one of the circuit-switched network orthe packet-switched network responsive to the handoff signal while thefirst voice connection is still established; and sending the voice dataassociated with the first voice connection with the networking deviceover the second voice connection with the networking device.
 14. Thecomputer-readable medium of claim 13 includes receiving the handoffsignal from the networking device over the first voice connection; andinitiating the establishment of the second voice connection with thenetworking device responsive to the handoff signal.
 15. Thecomputer-readable medium of claim 13 includes sending the handoff signalto the networking device over the first voice connection; and receivingan initiation of the second voice connection from the networking device.16. The computer-readable medium of claim 15 includes accessing aregistration server to determine an access address associated with thenetworking device; and sending the handoff signal to the access address.17. The computer-readable medium of claim 13 includes tearing down thefirst voice connection with the networking device after sending thevoice data over the second voice connection with the networking device.18. The computer-readable medium of claim 17 includes exchanging voicedata and at least one handoff signal with the networking device over thesecond voice connection; establishing a third voice connection with thenetworking device over the same network as the first voice connectionresponsive to the handoff signal; and sending the voice data associatedwith the second voice connection with the networking device over thethird voice connection with the networking device.
 19. Thecomputer-readable medium of claim 13 includes combining voice datareceived from both the first voice connection and the second voiceconnection into a voice data stream for auditory presentation at a phoneendpoint.
 20. A device comprising: means for establishing a first voiceconnection with a networking device over one of a circuit-switchednetwork or a packet-switched network; means for exchanging voice dataand at least one handoff signal with the networking device over thefirst voice connection, where the at least one handoff signal isexchanged with the networking device after exchanging the voice dataover the first voice connection to the networking device; means forestablishing a second voice connection with the networking device overthe other one of the circuit-switched network or the packet-switchednetwork responsive to the handoff signal while the first voiceconnection is still established; and means for sending the voice dataassociated with the first voice connection with the networking deviceover the second voice connection with the networking device.
 21. Thedevice of claim 20 including means for receiving the handoff signal fromthe networking device over the first voice connection; and means forinitiating the establishment of the second voice connection with thenetworking device responsive to the handoff signal.
 22. The device ofclaim 20 including means for sending the handoff signal to thenetworking device over the first voice connection; and means forreceiving an initiation of the second voice connection from thenetworking device.
 23. The device of claim 22 including means foraccessing a registration server to determine an access addressassociated with the networking device; and means for sending the handoffsignal to the access address.
 24. The device of claim 20 including meansfor tearing down the first voice connection with the networking deviceafter sending the voice data over the second voice connection with thenetworking device.
 25. The device of claim 24 including means forexchanging voice data and at least one handoff signal with thenetworking device over the second voice connection; means forestablishing a third voice connection with the networking device overthe same network as the first voice connection responsive to the handoffsignal; and means for sending the voice data associated with the secondvoice connection with the networking device over the third voiceconnection with the networking device.
 26. The device of claim 20including means for combining voice data received from both the firstvoice connection and the second voice connection into a voice datastream for auditory presentation at a phone endpoint.
 27. A devicecomprising: a network interface to exchange voice data with a networkingdevice over a circuit-switched network and a packet-switched network;voice connection circuitry to establish voice connections with thenetworking device over both the circuit-switched network and thepacket-switched network; handoff circuitry to determine which of thevoice connections exchanges voice data with the networking deviceresponsive to at least one handoff signal exchanged over one or more ofthe voice connections; and combining circuitry configured to combinevoice data received from both voice connections into a voice data streamfor auditory presentation at a phone endpoint.
 28. The device of claim27 where the network interface is configured to receive the handoffsignal from the networking device over one voice connection; and wherethe voice connection circuitry is configured to initiate theestablishment of the other voice connection with the networking deviceresponsive to the handoff signal.
 29. The device of claim 27 where thenetwork interface is configured to send the handoff signal to thenetworking device over one voice connection, and to receive aninitiation of another voice connection from the networking device. 30.The device of claim 29 where the network interface is configured toaccessing a registration server to determine an access addressassociated with the networking device, and to send the handoff signal tothe access address.
 31. The device of claim 27 where the voiceconnection circuitry is configured to tear down one of the voiceconnections with the networking device after sending the voice data overthe other voice connection with the networking device.
 32. The device ofclaim 27 where the network interface includes a circuit-switched networkinterface to exchange voice data with the networking device over thecircuit-switched network and a packet-switched network interface toexchange voice data with the networking device over the packet-switchednetwork.